Central Subway

May 2, 2013 11:49 AM

A construction worker prepares one of the two tunnel boring machines for extraction at Powell Street and Columbus Avenue in San Francisco, Calif. on Tuesday, June 25, 2014. Big Alma and Mom Chung have completed the tunneling portion of Muni's Central Subway project from South of Market to North Beach. less

A construction worker prepares one of the two tunnel boring machines for extraction at Powell Street and Columbus Avenue in San Francisco, Calif. on Tuesday, June 25, 2014. Big Alma and Mom Chung have completed ... more

Crews work on new Muni Metro subway station at Union Square -- drawing complaints from neighboring merchants.
A steel pile casing protrudes from the ground at O'Farrell and Stockton. The casing rotator (behind) is shown being moved with a crane. less

Crews work on new Muni Metro subway station at Union Square -- drawing complaints from neighboring merchants.
A steel pile casing protrudes from the ground at O'Farrell and Stockton. The casing rotator ... more

Photo: Robert J. Pierce, Municipal Transportation Agency

Crews work on new Muni Metro subway station at Union Square --... Photo-6925434.61527 - GreenwichTime

The cutter heads of Big Alma and Mom Chung are visible where contruction crews will raise them from below at Powell Street and Columbus Avenue in San Francisco, Calif. on Tuesday, June 25, 2014. The two giant boring machines have completed the tunneling portion of Muni's Central Subway project from South of Market to North Beach. less

The cutter heads of Big Alma and Mom Chung are visible where contruction crews will raise them from below at Powell Street and Columbus Avenue in San Francisco, Calif. on Tuesday, June 25, 2014. The two giant ... more

Construction worker Kory Sepulveda gazes into the pit where other crews prepare to extract Big Alma and Mom Chung from underground at Powell Street and Columbus Avenue in San Francisco, Calif. on Tuesday, June 25, 2014. The two giant boring machines have completed the tunneling portion of Muni's Central Subway project from South of Market to North Beach. less

Construction worker Kory Sepulveda gazes into the pit where other crews prepare to extract Big Alma and Mom Chung from underground at Powell Street and Columbus Avenue in San Francisco, Calif. on Tuesday, June ... more

The giant cutting machines have broken through at the extraction point at the corner of Columbus and Powell Streets, in San Francisco, Calif. as seen on Thursday June 19, 2014. The two tunnel boring machines digging the Central Subway project have gnawed their way through subterranean SOMA, Union Square, Chinatown and North Beach, and are now ready to be yanked from the earth to be reconditioned and resold. less

The giant cutting machines have broken through at the extraction point at the corner of Columbus and Powell Streets, in San Francisco, Calif. as seen on Thursday June 19, 2014. The two tunnel boring machines ... more

Worker Eddie Oseguera directs the crane operator as he guides equipment into position at the extraction point at the corner of Columbus and Powell Streets, in San Francisco, Calif. on Thursday June 19, 2014. The two tunnel boring machines digging the Central Subway project have gnawed their way through subterranean SOMA, Union Square, Chinatown and North Beach, and are now ready to be yanked from the earth to be reconditioned and resold. less

Worker Eddie Oseguera directs the crane operator as he guides equipment into position at the extraction point at the corner of Columbus and Powell Streets, in San Francisco, Calif. on Thursday June 19, 2014. ... more

Visitors ride aboard a transport vehicle in the northbound tunnel of Muni's Central Subway tunneling project in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding their way north from Fourth and Bryant streets towards Chinatown and North Beach. less

Visitors ride aboard a transport vehicle in the northbound tunnel of Muni's Central Subway tunneling project in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom ... more

Construction workers prepare a section of curved retaining wall for installation inside the northbound tunnel of Muni's Central Subway project in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding their way north from Fourth and Bryant streets towards Chinatown and North Beach. less

Construction workers prepare a section of curved retaining wall for installation inside the northbound tunnel of Muni's Central Subway project in San Francisco, Calif. on Saturday, March 8, 2014. Two large ... more

Visitors are updated on construction inside the northbound tunnel of Muni's Central Subway in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding their way north from Fourth and Bryant streets towards Chinatown and North Beach. less

Visitors are updated on construction inside the northbound tunnel of Muni's Central Subway in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding ... more

Construction workers prepare a section of curved retaining wall for installation inside the northbound tunnel of Muni's Central Subway project in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding their way north from Fourth and Bryant streets towards Chinatown and North Beach. less

Construction workers prepare a section of curved retaining wall for installation inside the northbound tunnel of Muni's Central Subway project in San Francisco, Calif. on Saturday, March 8, 2014. Two large ... more

Assistant construction superintendent Andy Granger looks south from a tunnel for Muni's Central Subway project below Union Square in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding their way north from Fourth and Bryant streets towards Chinatown and North Beach. less

Assistant construction superintendent Andy Granger looks south from a tunnel for Muni's Central Subway project below Union Square in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, ... more

Muni project manager John Funghi (left) and spokesman Paul Rose ride aboard a transport vehicle inside the northbound tunnel of the transit agency's Central Subway project in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding their way north from Fourth and Bryant streets towards Chinatown and North Beach. less

Drilling work continues in the northbound tunnel of Muni's Central Subway project in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding their way north from Fourth and Bryant streets towards Chinatown and North Beach. less

Drilling work continues in the northbound tunnel of Muni's Central Subway project in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding their way ... more

R.W. Carpenter works on the curved retaining wall for the northbound tunnel of Muni's Central Subway project in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom Chung, are grinding their way north from Fourth and Bryant streets towards Chinatown and North Beach. less

R.W. Carpenter works on the curved retaining wall for the northbound tunnel of Muni's Central Subway project in San Francisco, Calif. on Saturday, March 8, 2014. Two large boring machines, Big Alma and Mom ... more

R.W. Carpenter works on the curved retaining wall for the... Photo-5995514.61527 - GreenwichTime

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Broken sections of underground pipe, removed for the Central Subway construction project, are stored at Fourth and Bryant streets in San Francisco, Calif. on Friday, Jan. 10, 2014. With three major transportation projects wrapping up last year, the tunneling project for Muni's new subway line is among the few still underway. less

Broken sections of underground pipe, removed for the Central Subway construction project, are stored at Fourth and Bryant streets in San Francisco, Calif. on Friday, Jan. 10, 2014. With three major ... more

Every day workers remove metal plates covering access points into the area under Stockton and Geary streets to work on relocating utilities for the Central Subway in San Francisco, Calif., Friday, February 17, 2012. At the end of the work day they replace the metal plates and hammer them into place. less

Every day workers remove metal plates covering access points into the area under Stockton and Geary streets to work on relocating utilities for the Central Subway in San Francisco, Calif., Friday, February 17, ... more

Heavy equipment in place for the construction of the Central Subway project through downtown San Francisco, Calif., along Fourth Street, between Harrison and Bryant Streets, on Friday July 13, 2012.

Heavy equipment in place for the construction of the Central Subway project through downtown San Francisco, Calif., along Fourth Street, between Harrison and Bryant Streets, on Friday July 13, 2012.

Heavy equipment in place for the construction of the Central... Photo-4563182.61527 - GreenwichTime

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Francisco Esquivel shovels mud away from the construction of the slurry walls for the Central Subway project through downtown San Francisco, Calif. along Fourth Street, between Harrison and Bryant Streets, on Friday July 13, 2012. less

Francisco Esquivel shovels mud away from the construction of the slurry walls for the Central Subway project through downtown San Francisco, Calif. along Fourth Street, between Harrison and Bryant Streets, on ... more

Drilling for core samples that will determine the composition of the earth before the tunnel digging begins, on the Central Subway project through downtown San Francisco, Calif., along Fourth Street, between Harrison and Bryant Streets, on Friday July 13, 2012. less

Drilling for core samples that will determine the composition of the earth before the tunnel digging begins, on the Central Subway project through downtown San Francisco, Calif., along Fourth Street, between ... more

Drilling for core samples that will determine the composition of... Photo-4563184.61527 - GreenwichTime

Image 24 of 33

Dino Asko emerges from a manhole where he was boring holes to reroute utilities under Geary St. for the Central Subway in San Francisco, Calif., Friday, February 17, 2012.

Dino Asko emerges from a manhole where he was boring holes to reroute utilities under Geary St. for the Central Subway in San Francisco, Calif., Friday, February 17, 2012.

Dino Asko emerges from a manhole where he was boring holes to... Photo-4479725.61527 - GreenwichTime

Image 25 of 33

The design for the Central Subway station at Union Square would add a new structure near the southeast corner of the plaza. The design aim is to fold into the setting as much as possible, and create new seating on the sides and the roof. less

The design for the Central Subway station at Union Square would add a new structure near the southeast corner of the plaza. The design aim is to fold into the setting as much as possible, and create new seating ... more

Photo: Courtesy MTA

The design for the Central Subway station at Union Square would add... Photo-3314855.61527 - GreenwichTime

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The design for the Central Subway station at Union Square would add a new structure near the southeast corner of the plaza. The design aim is to fold into the setting as much as possible, and create new seating on the sides and the roof.
Ran on: 09-12-2011
The design for the new subway station at Union Square is intended to fold it into the setting as much as possible. less

The design for the Central Subway station at Union Square would add a new structure near the southeast corner of the plaza. The design aim is to fold into the setting as much as possible, and create new seating ... more

Photo: Courtesy MTA

The design for the Central Subway station at Union Square would add... Photo-1817174.61527 - GreenwichTime

Image 27 of 33

The Central Subway project through downtown San Francisco, Calif. is well underway along Fourth Street, between Harrison and Bryant Streets, on Friday July 13, 2012.

The Central Subway project through downtown San Francisco, Calif. is well underway along Fourth Street, between Harrison and Bryant Streets, on Friday July 13, 2012.

Roland Medina, (left) and Will Stewart take core samples to determine the composition of the earth before the tunnel digging begins, on the Central Subway project through downtown San Francisco, Calif., along Fourth Street, between Harrison and Bryant Streets, on Friday July 13, 2012. less

Roland Medina, (left) and Will Stewart take core samples to determine the composition of the earth before the tunnel digging begins, on the Central Subway project through downtown San Francisco, Calif., along ... more